Antigenic analysis of Trichomonas vaginalis strains by quantitative fluorescent antibody methods.

Clones of 5 Trichomonas vaginalis strains, JH30A, JH31A, JH34A, JH162A, and JH384A, kept in liquid nitrogen (with DMSO serving as the cryoprotectant) after a few weeks of cultivation in axenic cultures, were analyzed for their antigenic properties by quantitative direct fluorescent antibody methods. Measurements of fluorescence of individual cells obtained with the aid of an ultramicrofluorometer indicated that each strain possessed unique antigens as well as antigens it shared with the other strains studied. The relative amounts of common antigens present in each strain were estimated primarily by calculating the percent of fluorescence reduction recorded for organisms stained with their homologous conjugates, nonadsorbed and adsorbed with the homologous and heterologous antigens (strains). Antigenic relationships among the strains were estimated on the basis of statistical analyses of the data obtained in direct, one-step inhibition, and adsorption staining.